(Fiori, Gateway, OData, Web Dispatcher, Hypercare)

This is a Fiori & Connectivity War Room Manual for ECC → S/4HANA Migrations.

Real-world Fiori, Gateway, and connectivity failures that silently destroy ECC → S/4HANA Go-Lives and corresponding proven Fixes.

In ECC, SAP GUI was the primary interface.

In S/4HANA, Fiori is mandatory, and everything depends on HTTP, Gateway, OData, and Web Dispatcher.

This shift introduces an entirely new failure domain that most ECC teams underestimate.

That single shift is responsible for most real-world migration failures.

This manual is not about general migration issues.

It is specifically about the domain where projects break in reality:

Fiori, Gateway, OData, Web Dispatcher, Connectivity, and Hypercare operations

In real projects, Basis and Architecture teams spend 30–50% of migration time debugging Fiori, OData, and connectivity issues—often during Go-Live and hypercare, when business impact is highest.

🚨 The Hidden Reality of S/4HANA Migrations

Most ECC → S/4HANA projects fail not because of data or conversion, but because:

1. Fiori becomes mandatory
2. Browser becomes the runtime
3. Gateway becomes the execution layer
4. OData becomes the integration backbone
5. Connectivity becomes business-critical

Suddenly, Basis consultants spend more time fixing Fiori, Gateway, and OData than core ABAP issues.

This is where Go-Lives collapse silently.

This manual documents the exact real-world failure scenarios that occur when GUI assumptions collide with Fiori reality.

🔥 What This Manual Is Actually About

This is a Fiori & Connectivity failure manual, covering:

✅ Fiori Failures

1. Launchpad not loading
2. Infinite login loops
3. Tiles visible but apps don’t open
4. Cache corruption
5. Browser-specific failures

✅ Gateway & OData Nightmares

1. System alias failures
2. RFC works in SM59 but fails in OData
3. /IWFND errors without dumps
4. Metadata failures
5. Service activation traps

✅ Connectivity Breakdowns

1. Web Dispatcher routing failures
2. SSL & certificate issues
3. CORS and browser security blocks
4. Reverse proxy failures
5. Load balancer session breaks

✅ Hypercare Reality

1. Gateway errors not monitored
2. Business detects failures before IT
3. Incident explosions
4. Fiori ops visibility gaps
5. Post-Go-Live chaos

🧠 How It’s Written

Every scenario follows a real war-room structure:

1. What the user reports
2. What teams usually misdiagnose
3. The real root cause
4. Where it breaks in Fiori/Gateway/Connectivity
5. The permanent fix
6. The verification method

This is a troubleshooting manual, not a study guide.

👥 Who This Is For

This is specifically for:

1. SAP Basis consultants
2. S/4HANA architects
3. Fiori consultants
4. Gateway/OData specialists
5. Web Dispatcher administrators
6. Hypercare & support leads

If your daily work includes:

1. /IWFND/MAINT_SERVICE
2. /IWFND/ERROR_LOG
3. Web Dispatcher configs
4. Fiori Launchpad issues
5. OData failures
6. Browser console debugging

This manual is written for you.

❌ Who This Is NOT For

1. Functional consultants
2. Beginners learning S/4
3. People looking for SAP tutorials
4. Certification preparation

This is operations and migration reality, not learning content.

📌 Why This Exists

SAP documentation explains how Fiori should work.

This manual explains why it fails in real projects.

It documents the silent killers:

1. The issues that don’t show dumps
2. The issues that don’t show logs
3. The issues that only appear at Go-Live
4. The issues that destroy confidence without errors

🧨 And Finally

If you are migrating to S/4HANA and you think:

“The hard part is conversion and data…”

You will discover the hard part is:

Fiori, Gateway, and Connectivity.

This manual exists for that reality.